OK, here is the deal. I have the original breaker panel fed by a 150 amp
line off of a new panel necessitated when an addition was added years ago.
The sub panel is fed by a line with three conductors and ground of the
correct size.
The inspector at the time ended up getting fired for enforcing code that was
not there. With this in mind, he said he wanted a #6 bare ground wire to
tie between the original panel and the new panel. That means it would be in
parallel to the ground in the service feed cable.
Was he full of it when he told me this? I have been "neating up" the panel
along with my renovations for my new basement workshop. The old panel was
wired by a left handed chip, or a big bird, it was so messy. I took all but
about 5 circuits out and re-organized the whole thing neatly and added a few
new circuits for the shop. I feel much better about it, and solved a few
mysteries that had always bothered me.
Jim in NC
---
This email is free from viruses and malware because avast! Antivirus protection is active.
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On Wed, 8 Oct 2014 09:24:15 -0400, "Morgans"
<[email protected]> wrote:
>OK, here is the deal. I have the original breaker panel fed by a 150 amp
>line off of a new panel necessitated when an addition was added years ago.
>The sub panel is fed by a line with three conductors and ground of the
>correct size.
>
>The inspector at the time ended up getting fired for enforcing code that was
>not there. With this in mind, he said he wanted a #6 bare ground wire to
>tie between the original panel and the new panel. That means it would be in
>parallel to the ground in the service feed cable.
>
>Was he full of it when he told me this? I have been "neating up" the panel
>along with my renovations for my new basement workshop. The old panel was
>wired by a left handed chip, or a big bird, it was so messy. I took all but
>about 5 circuits out and re-organized the whole thing neatly and added a few
>new circuits for the shop. I feel much better about it, and solved a few
>mysteries that had always bothered me.
>
>Jim in NC
>
>
>---
>This email is free from viruses and malware because avast! Antivirus protection is active.
>http://www.avast.com
I'm confused by all this, but assuming your feeding your sub panel
with three conductors and a ground sized for the OCD then the only
reason I can think of for the #6 is that its a separate building and
he wants a grounding system which varies from jurisdiction to
jurisdiction. #6 being the largest size required to a grounding rod.
MikeM
On Wed, 8 Oct 2014 22:39:32 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>
>>> With N and G only tied together in one place, at the entrance panel
>>> (which may not be either of the two panels).
>> Which in his case, according to the initial post, IS the main panel
>> (and way back when, USED to be the sub panel - which means the sub
>> panel may or may not be a legally allowed sub-panel. If it had the
>> main braker or fuse in the panel, there is a STRONG possibility the
>> neutral and ground are permanently bonded (does not have a removeable
>> jumper))
>> Some of those panels CAN ge hacked or modified to separate the neutral
>> from the ground - some can not easily be modified. (and if it is
>> truely "modified" it is no longer an approved electrical device, so
>> again it is not code compliant - so we will ASS U ME this is a
>> compliant insulated(or isolated) neutral panel.
>
>Down here a main panel will always have a bonding screw so it can be used as
>either a main or a sub panel. It's been that way for ages. Don't know
>about panels up there though.
Not sure of current panels, but entrance panels (those with the main
breaker built in) a few years back often did not have the bonding
screw, while panels manufactured without the built-in main breaker
(separate - not taking up a "load" slot) most often did have the
removeable bonding screw.
On 10/08/2014 06:24 AM, Morgans wrote:
> OK, here is the deal. I have the original breaker panel fed by a 150
> amp line off of a new panel necessitated when an addition was added
> years ago. The sub panel is fed by a line with three conductors and
> ground of the correct size.
>
> The inspector at the time ended up getting fired for enforcing code that
> was not there. With this in mind, he said he wanted a #6 bare ground
> wire to tie between the original panel and the new panel. That means it
> would be in parallel to the ground in the service feed cable.
>
> Was he full of it when he told me this? I have been "neating up" the
> panel along with my renovations for my new basement workshop. The old
> panel was wired by a left handed chip, or a big bird, it was so messy.
> I took all but about 5 circuits out and re-organized the whole thing
> neatly and added a few new circuits for the shop. I feel much better
> about it, and solved a few mysteries that had always bothered me.
>
> Jim in NC
>
> ---
> This email is free from viruses and malware because avast! Antivirus
> protection is active.
> http://www.avast.com
>
Not sure the extra heavy duty ground hurts anything, but make sure the
ground and neutral are not tied together in the sub panel - in other
words, separate neutral and ground bus bars and no bonding strap from
the neutral bus bar to the sub panel case.
--
"Socialism is a philosophy of failure,the creed of ignorance, and the
gospel of envy, its inherent virtue is the equal sharing of misery"
-Winston Churchill
"Morgans" <[email protected]> wrote in
news:[email protected]:
> OK, here is the deal. I have the original breaker panel fed by a 150
> amp line off of a new panel necessitated when an addition was added
> years ago. The sub panel is fed by a line with three conductors and
> ground of the correct size.
>
> The inspector at the time ended up getting fired for enforcing code
> that was not there. With this in mind, he said he wanted a #6 bare
> ground wire to tie between the original panel and the new panel. That
> means it would be in parallel to the ground in the service feed cable.
I think we're getting confused here. How many pieces of copper are in
the feed? 3 or 4?
A second wire, outside the feed, is connected from panel to panel as a
ground, right?
> Was he full of it when he told me this? I have been "neating up" the
> panel along with my renovations for my new basement workshop. The old
> panel was wired by a left handed chip, or a big bird, it was so messy.
> I took all but about 5 circuits out and re-organized the whole thing
> neatly and added a few new circuits for the shop. I feel much better
> about it, and solved a few mysteries that had always bothered me.
>
> Jim in NC
>
>
Puckdropper
--
Make it to fit, don't make it fit.
On 10/09/2014 04:14 AM, Mike Marlow wrote:
> Morgans wrote:
>
>> This additional ground wire the inspector wanted was to be a #6 bare
>> copper wire connected at the main panel (service entrance) onto the
>> ground/neutral buss and then run to the sub panel and connected to
>> the ground buss. (which is bonded to the frame)
>>
>> I believe Clair read my description correctly, and that the two #6
>> bare copper and the ground conductor in the cable are connected to
>> the same things in each panel, and they are parallel, and that the #6
>> is indeed above code and unnecessary.
>
> That would be correct - in parallel if they are connected to the same things
> on each end. Don't understand why your inspector required such a thing
> though.
>
>
Probably thought that the grounding wire in the cable wasn't big enough?
--
"Socialism is a philosophy of failure,the creed of ignorance, and the
gospel of envy, its inherent virtue is the equal sharing of misery"
-Winston Churchill
On 10/08/2014 10:20 PM, Morgans wrote:
>
>
> "Puckdropper" <puckdropper(at)yahoo(dot)com> wrote in message
> news:[email protected]...
>> "Morgans" <[email protected]> wrote in
>> news:[email protected]:
>>
>>> OK, here is the deal. I have the original breaker panel fed by a 150
>>> amp line off of a new panel necessitated when an addition was added
>>> years ago. The sub panel is fed by a line with three conductors and
>>> ground of the correct size.
>>>
>>> The inspector at the time ended up getting fired for enforcing code
>>> that was not there. With this in mind, he said he wanted a #6 bare
>>> ground wire to tie between the original panel and the new panel. That
>>> means it would be in parallel to the ground in the service feed cable.
>>
>> I think we're getting confused here. How many pieces of copper are in
>> the feed? 3 or 4?
>
> 4, but they are aluminum. Two hots and a neutral, all three insulated,
> with additional bare conductor.
Didja use the black gunk (anti-oxidant paste) on all the aluminum wire
panel connections?
--
"Socialism is a philosophy of failure,the creed of ignorance, and the
gospel of envy, its inherent virtue is the equal sharing of misery"
-Winston Churchill
"Morgans" wrote:
> OK, here is the deal. I have the original breaker panel fed by a
> 150 amp line off of a new panel necessitated when an addition was
> added years ago. The sub panel is fed by a line with three
> conductors and ground of the correct size.
----------------------------------------------
Somebody had it right.
Mike Marlow maybe.
A sub panel requires an insulated ground buss as well as an
insulated neutral buss.
In addition, a sub panel must be able to disconnect all power
under it's control in a maximum of six (6) motions of the hand;
otherwise known as the six (6) hand rule.
If more than (6) motions are required to disconnect all branches,
then a main c'bkr is required.
SFWIW, a branch c'bkr located in the main panel and feeding the
sub panel is also required.
The bonding strap located in the sub panel shall be connected to
the insulated ground buss.
The sub panel shall be fed by four (4) conductors (L1, L2, N and G)
from the main panel.
The neutral buss and ground buss in the main panel do not have
to be insulated but often are.
The bonding strap located in the main panel shall be connected to
the ground buss.
The neutral buss and ground buss in the main panel are tied together
as well as the earth ground conductor which connects to the earth
ground rod driven into the earth at the service point.
The above meets code or did when I was in the business.
Nothing else is required.
Lew
>> OTOH, he said,
>>
>> "A sub panel requires an insulated ground buss as well as
>> an insulated neutral buss."
>
-------------------------------------------------------------
"John McCoy" wrote:
> I wonder if the source Lew was quoting meant an "isolated"
> ground bus (i.e. isolated from the neutral) rather than
> insulated.
>
> Because I'm with you, insulated ground bus doesn't seem to
> make sense, when you're going to strap it to the case anyway.
------------------------------------------------------------------
If you read and understand what was written, you will see that
my comments are correct as written.
The NEC does NOT permit multiple paths to ground, but rather
only allows a single path between a fault and earth ground.
INSULATED neutral buss and ground buss bars mounted and
wired ONLY as described will meet those NEC requirements
of having ONLY a single path from fault to ground.
Yes it does make a difference how a system is wired and the
equipment used in order to meet the NEC requirements.
Lew
On Sat, 11 Oct 2014 13:54:01 +0000 (UTC), John McCoy
<[email protected]> wrote:
>[email protected] wrote in news:[email protected]:
>
>> OTOH, he said,
>>
>> "A sub panel requires an insulated ground buss as well as
>> an insulated neutral buss."
>
>I wonder if the source Lew was quoting meant an "isolated"
>ground bus (i.e. isolated from the neutral) rather than
>insulated.
>
>Because I'm with you, insulated ground bus doesn't seem to
>make sense, when you're going to strap it to the case anyway.
>
>John
I would also vote for an "isolated" bus.
On Sat, 11 Oct 2014 11:35:40 -0400, [email protected] wrote:
>On Sat, 11 Oct 2014 13:54:01 +0000 (UTC), John McCoy
><[email protected]> wrote:
>
>>[email protected] wrote in news:[email protected]:
>>
>>> OTOH, he said,
>>>
>>> "A sub panel requires an insulated ground buss as well as
>>> an insulated neutral buss."
>>
>>I wonder if the source Lew was quoting meant an "isolated"
>>ground bus (i.e. isolated from the neutral) rather than
>>insulated.
>>
>>Because I'm with you, insulated ground bus doesn't seem to
>>make sense, when you're going to strap it to the case anyway.
>>
>>John
> I would also vote for an "isolated" bus.
Ground "isolated" from the neutral, not from the case. It is screwed
right to the case.
On 10/9/2014 9:45 PM, Martin Eastburn wrote:
> On 10/9/2014 10:29 AM, Mike Marlow wrote:
>> Doug Winterburn wrote:
>>> On 10/09/2014 04:14 AM, Mike Marlow wrote:
>>>> Morgans wrote:
>>>>
>>>>> This additional ground wire the inspector wanted was to be a #6 bare
>>>>> copper wire connected at the main panel (service entrance) onto the
>>>>> ground/neutral buss and then run to the sub panel and connected to
>>>>> the ground buss. (which is bonded to the frame)
>>>>>
>>>>> I believe Clair read my description correctly, and that the two #6
>>>>> bare copper and the ground conductor in the cable are connected to
>>>>> the same things in each panel, and they are parallel, and that the
>>>>> #6 is indeed above code and unnecessary.
>>>>
>>>> That would be correct - in parallel if they are connected to the
>>>> same things on each end. Don't understand why your inspector
>>>> required such a thing though.
>>>>
>>>>
>>> Probably thought that the grounding wire in the cable wasn't big
>>> enough?
>>
>> Could be.
>>
> Was there a metal shop there - not grounded and he was trying to put in
> lighting protection with a large wire ?
> I'd think Grounding it Local and having a safety line is all that was
> needed. The closest the house and addition get to each other is at
> the transformer.
>
> I have HV 2 phase into my place. Shop is a drop with a meter.
> The house is a drop with a meter.
> The 28x70' addition is a drop with a meter.
>
> Yep three meters. Three ground rods with a fourth for the Sat. TV.
> One transformer feeds house and addition. Shop has another pole &
> transformer.
>
> The shop is 600' from the road having 3phase HV and the house is another
> 600' (more). I had 1500 feet of 2 phase into the property,
> but a storm brought down the end pole and caused havoc!
>
> My addition:
> Once I told the Electrical Engineer (loosely stated there) the intended
> load size, they put in a new circuit rather than dropping one out of the
> box.
>
> The drop to the addition was about 150' long from the pole. Wires
> and concrete made an end around loop.
>
> Martin
I totally forgot the sub panel in the Greenhouse. 220v two poles,
neutral and ground. I have both 220 and 120 volt breakers and circuits.
I had planned on a large heater and fan. I might just try a large
industrial 6' ceramic coil in a reflector and a temp control.
Testing will be interesting. Hope it works.
Martin
"Mike Marlow" <[email protected]> wrote in
news:[email protected]:
> [email protected] wrote:
>
>> The feed wire was a 3 wire+ground cable The ground was connected to
>> both panels. Adding the #6 bare copper ground between the two panels
>> would, by necessity and the nature of the circuit, mean that the bare
>> ground WAS in parallel with the ground in the feed cable.
>
> No - it would not. To be in parallel both ends would have to share a
> common connection.
Yes, it is. If I have a point defined as ground at one end of
wire, and I connect the other end of that wire to something,
the other end is also ground. If I then take a second wire
and connect it to both ends, the second wire is in parallel
to the first wire. That is the situation being described.
> NEC requires a 4 wire feed to a sub panel - assuming 240v. Two hots,
> a neutral and a separate ground that is only connected back to the
> main panel ground (which makes it NOT in parallel).
You have misread the original post. He said he has a four
wire cable, and _in addition_ he has another #6 ground wire.
The additional ground wire is redundant, but harmless (it
might be helpful in the event of a lightning strike, but
otherwise it serves no purpose).
John
DJ Delorie <[email protected]> wrote in news:[email protected]:
> If both grounds are
> connected on both ends, there's a loop. Is a loop in a ground allowed?
The situation described is topologically a loop, but not
electrically.
> Are ground loops legal?
"ground loop" means something else in the world of electricity.
John
"Morgans" <[email protected]> wrote in news:[email protected]:
> OK, here is the deal. I have the original breaker panel fed by a 150 amp
> line off of a new panel necessitated when an addition was added years ago.
> The sub panel is fed by a line with three conductors and ground of the
> correct size.
>
> The inspector at the time ended up getting fired for enforcing code that was
> not there. With this in mind, he said he wanted a #6 bare ground wire to
> tie between the original panel and the new panel. That means it would be in
> parallel to the ground in the service feed cable.
And that's a Code violation AFAIK.
> Was he full of it when he told me this?
Yes, he was. AFAIK, anyway.
If you want a definitive answer, repost this in alt.home.repair, titled "PING: gfretwell re
subpanel grounding". Greg (?) Fretwell is a licensed electrician who is a regular in that
group, and whatever advice he gives you, you can take to the bank.
[email protected] wrote in news:[email protected]:
> On Wed, 8 Oct 2014 22:02:26 +0000 (UTC), John McCoy
> <[email protected]> wrote:
>
>>DJ Delorie <[email protected]> wrote in news:[email protected]:
>>
>>> If both grounds are
>>> connected on both ends, there's a loop. Is a loop in a ground allowed?
>>
>>The situation described is topologically a loop, but not
>>electrically.
>
> Actually, it is. If the two wires are routed separately (if they're
> run absolutely together, its one wire), there is a loop or a "one-turn
> transformer", if you will. That's why it's not allowed.
The situation described has them both in the same conduit,
if I'm not mistaken. That's not a loop, that's just two
parallel conductors (and, if the conduit is EMT, then it's
three parallel conductors).
John
[email protected] wrote in news:[email protected]:
> OTOH, he said,
>
> "A sub panel requires an insulated ground buss as well as
> an insulated neutral buss."
I wonder if the source Lew was quoting meant an "isolated"
ground bus (i.e. isolated from the neutral) rather than
insulated.
Because I'm with you, insulated ground bus doesn't seem to
make sense, when you're going to strap it to the case anyway.
John
"Lew Hodgett" <[email protected]> wrote in news:54395b42$0$64426
[email protected]:
> The NEC does NOT permit multiple paths to ground, but rather
> only allows a single path between a fault and earth ground.
Actually it does. If you read the NEC you'll find several
instances where multiple grounds are described. In general
every building is allowed to have a ground.
What the NEC cares about is having only a single path for
the neutral (which they occasionally call the "grounded
conductor", just to make things confusing).
> INSULATED neutral buss and ground buss bars mounted and
> wired ONLY as described will meet those NEC requirements
> of having ONLY a single path from fault to ground.
I cannot find this wording in the NEC(*), at least not in section
250.30, which I think is the relevant section for subpanels.
All that that section specifies is that the neutral on the
subpanel be isolated (and it does say isolated, not insulated).
> Yes it does make a difference how a system is wired and the
> equipment used in order to meet the NEC requirements.
It definately does, and no-one is disputing that. However I
think your source is going beyond the NEC, and is perhaps
looking at a specific situation rather than the general case
(in particular, I think it's looking at a situation where
the ground is tied to the neutral, and the neutral is bonded
to the case. In that situation to use the panel for a subpanel
the tie between neutral and ground and the bond to the case
must be removed, and a new bond between ground and case added).
John
(* 2008 handbook, I don't have access to the 2014 edition).
On Sat, 11 Oct 2014 09:31:01 -0700, "Lew Hodgett"
<[email protected]> wrote:
>>> OTOH, he said,
>>>
>>> "A sub panel requires an insulated ground buss as well as
>>> an insulated neutral buss."
>>
>
>-------------------------------------------------------------
>
>"John McCoy" wrote:
>
>> I wonder if the source Lew was quoting meant an "isolated"
>> ground bus (i.e. isolated from the neutral) rather than
>> insulated.
>>
>> Because I'm with you, insulated ground bus doesn't seem to
>> make sense, when you're going to strap it to the case anyway.
>------------------------------------------------------------------
>If you read and understand what was written, you will see that
>my comments are correct as written.
>
>The NEC does NOT permit multiple paths to ground, but rather
>only allows a single path between a fault and earth ground.
>
>INSULATED neutral buss and ground buss bars mounted and
>wired ONLY as described will meet those NEC requirements
>of having ONLY a single path from fault to ground.
Wrong. Ground bars are *not* insulated/isolated from the case.
Neutral bars are and strapped when necessary.
>Yes it does make a difference how a system is wired and the
>equipment used in order to meet the NEC requirements.
Yes, but you're still wrong.
On 10/9/2014 10:29 AM, Mike Marlow wrote:
> Doug Winterburn wrote:
>> On 10/09/2014 04:14 AM, Mike Marlow wrote:
>>> Morgans wrote:
>>>
>>>> This additional ground wire the inspector wanted was to be a #6 bare
>>>> copper wire connected at the main panel (service entrance) onto the
>>>> ground/neutral buss and then run to the sub panel and connected to
>>>> the ground buss. (which is bonded to the frame)
>>>>
>>>> I believe Clair read my description correctly, and that the two #6
>>>> bare copper and the ground conductor in the cable are connected to
>>>> the same things in each panel, and they are parallel, and that the
>>>> #6 is indeed above code and unnecessary.
>>>
>>> That would be correct - in parallel if they are connected to the
>>> same things on each end. Don't understand why your inspector
>>> required such a thing though.
>>>
>>>
>> Probably thought that the grounding wire in the cable wasn't big
>> enough?
>
> Could be.
>
Was there a metal shop there - not grounded and he was trying to put in
lighting protection with a large wire ?
I'd think Grounding it Local and having a safety line is all that was
needed. The closest the house and addition get to each other is at
the transformer.
I have HV 2 phase into my place. Shop is a drop with a meter.
The house is a drop with a meter.
The 28x70' addition is a drop with a meter.
Yep three meters. Three ground rods with a fourth for the Sat. TV.
One transformer feeds house and addition. Shop has another pole &
transformer.
The shop is 600' from the road having 3phase HV and the house is another
600' (more). I had 1500 feet of 2 phase into the property,
but a storm brought down the end pole and caused havoc!
My addition:
Once I told the Electrical Engineer (loosely stated there) the intended
load size, they put in a new circuit rather than dropping one out of the
box.
The drop to the addition was about 150' long from the pole. Wires
and concrete made an end around loop.
Martin
On Wed, 08 Oct 2014 19:22:39 -0400, [email protected] wrote:
>On 08 Oct 2014 21:04:39 GMT, Puckdropper
><puckdropper(at)yahoo(dot)com> wrote:
>
>>"Morgans" <[email protected]> wrote in
>>news:[email protected]:
>>
>>> OK, here is the deal. I have the original breaker panel fed by a 150
>>> amp line off of a new panel necessitated when an addition was added
>>> years ago. The sub panel is fed by a line with three conductors and
>>> ground of the correct size.
>>>
>>> The inspector at the time ended up getting fired for enforcing code
>>> that was not there. With this in mind, he said he wanted a #6 bare
>>> ground wire to tie between the original panel and the new panel. That
>>> means it would be in parallel to the ground in the service feed cable.
>>
>>I think we're getting confused here. How many pieces of copper are in
>>the feed? 3 or 4?
>
>4
>L1, L2, N and Grnd
With N and G only tied together in one place, at the entrance panel
(which may not be either of the two panels).
On Fri, 10 Oct 2014 18:35:35 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>
>>
>> Insulated ground bus (one 's', two and it's a kiss)? Why insulated?
>> It has to be bonded to the case. The neutral has to be isolated from
>> the ground, sure.
>
>No - an insulated neutral. The neutral must be isolated from the ground.
>It's in the NEC.
Right, but that's *not* what Lew said. Go back and read what you
snipped.
>>
>>> The bonding strap located in the sub panel shall be connected to
>>> the insulated ground buss.
>>
>> Again, why insulated? That makes *no* sense.
>
>It's not required but it is common in a 4 wire feed.
The ground bus is *not* isolated in a common panel. The neutral bus
*is* (with a link to bond it in the entrance).
On Sat, 11 Oct 2014 22:34:47 -0400, [email protected] wrote:
>On Sat, 11 Oct 2014 16:24:33 -0400, [email protected] wrote:
>
>>On Sat, 11 Oct 2014 09:31:01 -0700, "Lew Hodgett"
>><[email protected]> wrote:
>>
>>>>> OTOH, he said,
>>>>>
>>>>> "A sub panel requires an insulated ground buss as well as
>>>>> an insulated neutral buss."
>>>>
>>>
>>>-------------------------------------------------------------
>>>
>>>"John McCoy" wrote:
>>>
>>>> I wonder if the source Lew was quoting meant an "isolated"
>>>> ground bus (i.e. isolated from the neutral) rather than
>>>> insulated.
>>>>
>>>> Because I'm with you, insulated ground bus doesn't seem to
>>>> make sense, when you're going to strap it to the case anyway.
>>>------------------------------------------------------------------
>>>If you read and understand what was written, you will see that
>>>my comments are correct as written.
>>>
>>>The NEC does NOT permit multiple paths to ground, but rather
>>>only allows a single path between a fault and earth ground.
>>>
>>>INSULATED neutral buss and ground buss bars mounted and
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>wired ONLY as described will meet those NEC requirements
>>>of having ONLY a single path from fault to ground.
>>
>>Wrong. Ground bars are *not* insulated/isolated from the case.
>>Neutral bars are and strapped when necessary.
>
>Nowhere did he say what you say he said. He said: Insulated neutral
>busses ---- and ground busses mounted and wires only as described ---
>will meet those NEC requirements.
Wrong. "INSULATED neutral buss and ground buss bars" means the both
are INSULATED (the symmetry of the phrase indicates such). Since he
refuses to clarify...
>He did not say: Insulated neutral bus and ground bus bars --- mounted
>and wires ONLY as described --- will meat those NEC requirements.
That's *exactly* what he did say. It may not be what he meant but
it's what he said.
> So no, he was NOT wrong.
>
>You just chose to read it wrong.
Perhaps he wrote it wrong but since he refuses to clarify...
>>
>>>Yes it does make a difference how a system is wired and the
>>>equipment used in order to meet the NEC requirements.
>>
>>Yes, but you're still wrong.
>And so are you - - - - in the interpretation of what he wrote.
You must be illiterate.
On 08 Oct 2014 21:04:39 GMT, Puckdropper
<puckdropper(at)yahoo(dot)com> wrote:
>"Morgans" <[email protected]> wrote in
>news:[email protected]:
>
>> OK, here is the deal. I have the original breaker panel fed by a 150
>> amp line off of a new panel necessitated when an addition was added
>> years ago. The sub panel is fed by a line with three conductors and
>> ground of the correct size.
>>
>> The inspector at the time ended up getting fired for enforcing code
>> that was not there. With this in mind, he said he wanted a #6 bare
>> ground wire to tie between the original panel and the new panel. That
>> means it would be in parallel to the ground in the service feed cable.
>
>I think we're getting confused here. How many pieces of copper are in
>the feed? 3 or 4?
4
L1, L2, N and Grnd
>
>A second wire, outside the feed, is connected from panel to panel as a
>ground, right?
A fifth wire, if you want to be accurate., or a second ground.
>
>> Was he full of it when he told me this? I have been "neating up" the
>> panel along with my renovations for my new basement workshop. The old
>> panel was wired by a left handed chip, or a big bird, it was so messy.
>> I took all but about 5 circuits out and re-organized the whole thing
>> neatly and added a few new circuits for the shop. I feel much better
>> about it, and solved a few mysteries that had always bothered me.
>>
>> Jim in NC
>>
>>
>
>Puckdropper
On Wed, 08 Oct 2014 19:28:03 -0400, [email protected] wrote:
>On Wed, 08 Oct 2014 19:22:39 -0400, [email protected] wrote:
>
>>On 08 Oct 2014 21:04:39 GMT, Puckdropper
>><puckdropper(at)yahoo(dot)com> wrote:
>>
>>>"Morgans" <[email protected]> wrote in
>>>news:[email protected]:
>>>
>>>> OK, here is the deal. I have the original breaker panel fed by a 150
>>>> amp line off of a new panel necessitated when an addition was added
>>>> years ago. The sub panel is fed by a line with three conductors and
>>>> ground of the correct size.
>>>>
>>>> The inspector at the time ended up getting fired for enforcing code
>>>> that was not there. With this in mind, he said he wanted a #6 bare
>>>> ground wire to tie between the original panel and the new panel. That
>>>> means it would be in parallel to the ground in the service feed cable.
>>>
>>>I think we're getting confused here. How many pieces of copper are in
>>>the feed? 3 or 4?
>>
>>4
>>L1, L2, N and Grnd
>
>With N and G only tied together in one place, at the entrance panel
>(which may not be either of the two panels).
Which in his case, according to the initial post, IS the main panel
(and way back when, USED to be the sub panel - which means the sub
panel may or may not be a legally allowed sub-panel. If it had the
main braker or fuse in the panel, there is a STRONG possibility the
neutral and ground are permanently bonded (does not have a removeable
jumper))
Some of those panels CAN ge hacked or modified to separate the neutral
from the ground - some can not easily be modified. (and if it is
truely "modified" it is no longer an approved electrical device, so
again it is not code compliant - so we will ASS U ME this is a
compliant insulated(or isolated) neutral panel.
On Wed, 08 Oct 2014 19:33:45 -0400, [email protected] wrote:
>On Wed, 08 Oct 2014 19:28:03 -0400, [email protected] wrote:
>
>>On Wed, 08 Oct 2014 19:22:39 -0400, [email protected] wrote:
>>
>>>On 08 Oct 2014 21:04:39 GMT, Puckdropper
>>><puckdropper(at)yahoo(dot)com> wrote:
>>>
>>>>"Morgans" <[email protected]> wrote in
>>>>news:[email protected]:
>>>>
>>>>> OK, here is the deal. I have the original breaker panel fed by a 150
>>>>> amp line off of a new panel necessitated when an addition was added
>>>>> years ago. The sub panel is fed by a line with three conductors and
>>>>> ground of the correct size.
>>>>>
>>>>> The inspector at the time ended up getting fired for enforcing code
>>>>> that was not there. With this in mind, he said he wanted a #6 bare
>>>>> ground wire to tie between the original panel and the new panel. That
>>>>> means it would be in parallel to the ground in the service feed cable.
>>>>
>>>>I think we're getting confused here. How many pieces of copper are in
>>>>the feed? 3 or 4?
>>>
>>>4
>>>L1, L2, N and Grnd
>>
>>With N and G only tied together in one place, at the entrance panel
>>(which may not be either of the two panels).
> Which in his case, according to the initial post, IS the main panel
>(and way back when, USED to be the sub panel - which means the sub
>panel may or may not be a legally allowed sub-panel.
The post was confusing. Not sure exactly what he has but the point is
still valid. It's possible that none of these panels are the
"entrance". They haven't been in either of my last houses.
>If it had the
>main braker or fuse in the panel, there is a STRONG possibility the
>neutral and ground are permanently bonded (does not have a removeable
>jumper))
The separate ground bars are available for many of these boxes. I
agree, though, it sounds like they may not be wired so they're
separable. They can be rewired (if the parts are available for the
boxes).
>Some of those panels CAN ge hacked or modified to separate the neutral
>from the ground - some can not easily be modified. (and if it is
>truely "modified" it is no longer an approved electrical device, so
>again it is not code compliant - so we will ASS U ME this is a
>compliant insulated(or isolated) neutral panel.
Hacking, of course, wouldn't be allowed. The boxes and all hardware
have to be listed for the purpose. These parts are often available,
though.
Morgans wrote:
> OK, here is the deal. I have the original breaker panel fed by a 150
> amp line off of a new panel necessitated when an addition was added years
> ago. The sub panel is fed by a line with three conductors and ground of
> the
> correct size.
Just to clarify Jim - what was once the "original" panel is now a sub-panel?
>
> The inspector at the time ended up getting fired for enforcing code
> that was not there. With this in mind, he said he wanted a #6 bare ground
> wire to tie between the original panel and the new panel. That means it
> would be in parallel to the ground in the service feed cable.
No - it doesn't. The ground only shares one point in common between the two
panels so it can't be in parallel. Not so sure about the #6 aspect of what
he wanted, but the connection between the two panels (main and sub) is
exactly to the NEC spec. If he got fired for that then whoever fired him
should be fired themselves. It does not have to be a bare ground - an
insulated ground is perfectly acceptable. Bare ground is only specified for
grounding stakes.
--
-Mike-
[email protected]
Doug Winterburn wrote:
>>
> Not sure the extra heavy duty ground hurts anything, but make sure the
> ground and neutral are not tied together in the sub panel - in other
> words, separate neutral and ground bus bars and no bonding strap from
> the neutral bus bar to the sub panel case.
Echo
--
-Mike-
[email protected]
[email protected] wrote:
> The feed wire was a 3 wire+ground cable The ground was connected to
> both panels. Adding the #6 bare copper ground between the two panels
> would, by necessity and the nature of the circuit, mean that the bare
> ground WAS in parallel with the ground in the feed cable.
No - it would not. To be in parallel both ends would have to share a common
connection. It is simply a branch back to the original ground - and that is
the purpose of it - so that there is only ONE path to ground. To be in
parallel, it would be necessary to put in an additional ground rod at the
sub panel end - which is not in compliance with NEC.
> If the ground in the feed cable meats the requirement of code (which
> I am 99.999% certain it does) then requiring the extra basre ground
> was a requirement beyond code, and he needed his knucles rapped good.
> I suspect this was not his first infraction for requiring "above code"
> - hense his firing. Good riddance.
NEC requires a 4 wire feed to a sub panel - assuming 240v. Two hots, a
neutral and a separate ground that is only connected back to the main panel
ground (which makes it NOT in parallel). Does not matter what makes sense
to you - that is the NEC. As I said - the bare ground did not make any
sense to me and I'm not sure that's what was really specified but if it was,
don't make any sense - but the separate ground does indeed make a lot of
sense - it's the NEC.
--
-Mike-
[email protected]
DJ Delorie wrote:
> "Mike Marlow" <[email protected]> writes:
>> No - it doesn't. The ground only shares one point in common between
>> the two panels so it can't be in parallel.
>
> His point is that there are now TWO grounds between the panels, the
> insulated one in the cable and a separate bare #6. If both grounds
> are connected on both ends, there's a loop. Is a loop in a ground
> allowed?
No - it is not allowed, but I don't even see that in what he originally
stated. Maybe I missed something?
>
>> If he got fired for that
>
> I didn't get that impression. It sounded like he got fired for
> enforcing nonexisting rules elsewhere, but the OP didn't say he was
> fired for *this* case. The OP implied that he now suspects the
> inspector's requirements *because* he was fired.
>
> So IMHO the case is - the OP is now suspicious, and wants a second
> opinion. Are bare grounds required? Are ground loops legal?
Bare grounds are not required and ground loops are not allowed. But -
man... you read a lot more into that than I did.
--
-Mike-
[email protected]
Puckdropper wrote:
> "Morgans" <[email protected]> wrote in
> news:[email protected]:
>
>> OK, here is the deal. I have the original breaker panel fed by a 150
>> amp line off of a new panel necessitated when an addition was added
>> years ago. The sub panel is fed by a line with three conductors and
>> ground of the correct size.
>>
>> The inspector at the time ended up getting fired for enforcing code
>> that was not there. With this in mind, he said he wanted a #6 bare
>> ground wire to tie between the original panel and the new panel.
>> That means it would be in parallel to the ground in the service feed
>> cable.
>
> I think we're getting confused here. How many pieces of copper are in
> the feed? 3 or 4?
>
Not usually copper in a sub-feed. Usually aluminum. Not really a big
deal - copper would in fact be better.
> A second wire, outside the feed, is connected from panel to panel as a
> ground, right?
??? Usually one would pull a 4 wire feed between the two - two hots, a
neutral, and a ground - all of which are semi-wrapped around each other as a
single bundle. So - nothing "outside the feed".
--
-Mike-
[email protected]
[email protected] wrote:
>> With N and G only tied together in one place, at the entrance panel
>> (which may not be either of the two panels).
> Which in his case, according to the initial post, IS the main panel
> (and way back when, USED to be the sub panel - which means the sub
> panel may or may not be a legally allowed sub-panel. If it had the
> main braker or fuse in the panel, there is a STRONG possibility the
> neutral and ground are permanently bonded (does not have a removeable
> jumper))
> Some of those panels CAN ge hacked or modified to separate the neutral
> from the ground - some can not easily be modified. (and if it is
> truely "modified" it is no longer an approved electrical device, so
> again it is not code compliant - so we will ASS U ME this is a
> compliant insulated(or isolated) neutral panel.
Down here a main panel will always have a bonding screw so it can be used as
either a main or a sub panel. It's been that way for ages. Don't know
about panels up there though.
--
-Mike-
[email protected]
[email protected] wrote:
> You definition is strange. 2 wires, connected to the same thing at
> each end, put the 2 wires in parallel, and they would share the fault
> load if power was to short to the panel frame at the "load " end.
That is exactly what I had stated - they have to be connected to the same
thing at each end. The OP's statement was different though - had stated (as
I understood it), that simply running a ground wire put the two panels in
parallel. That's a different colored horse.
>
> It is connected to the main panel ground at the main panel end. So is
> the bare (or green) wire in the 3 wire+ground cable to the sub panel.
> It is connected to the ground terminal of the sub panel. So is the
> bare wire (or green) in the cable from the main panel. That puts the
> two grounds in parallel. It is also "effectively" in parallel with the
> white neutral, although not "exactly".
Absolutely NOT exactly. The neutral is floated and is not at all in
parallel with the ground at the sub panel. That's the intended design by
NEC. There is no need for both of those grounds. Only one ground between
the main and the sub panel are required per the NEC. There would not be any
need for two grounds in parallel. I think there is some confusion about
what really exists in the OP's configuration.
--
-Mike-
[email protected]
Markem wrote:
> On Wed, 8 Oct 2014 22:02:26 +0000 (UTC), John McCoy
> <[email protected]> wrote:
>
>> DJ Delorie <[email protected]> wrote in news:[email protected]:
>>
>>> If both grounds are
>>> connected on both ends, there's a loop. Is a loop in a ground
>>> allowed?
>>
>> The situation described is topologically a loop, but not
>> electrically.
>>
>>> Are ground loops legal?
>>
>> "ground loop" means something else in the world of electricity.
>>
>> John
>
> A ground loop hums at about 60 hz as I recall, not that I ever hooked
> up one. Well maybe one at a mic input.
>
> Mark
Yup - or at 50Hz in Europe. Or at a harmonic of the base frequency...
--
-Mike-
[email protected]
OK, I will try to be more clear.
I have a three conductor with additional ground conductor cable going
between panels. In the main panel, fed from the road, the neutral and
grounds are equal, with the normal configuration of the neutral and grounds
bonded to the panel frame, and the whole thing grounded to a ground rod and
to the neutral coming in from the pole.
In the sub panel, which was the house's original panel, the neutral is not
bonded to the frame of the panel, and there is a separate grounding lug
connected and bonded to the frame of the panel.
Now for what the cable coming from the main panel is connected to. Remember
that it is two hot wires (insulated) a neutral wire (insulated) and
grounding wire wrapped as individual strands around all of the insulated
conductors, and all of it covered in plastic sheathing. The two hot wires
are of course connected to the two breaker busses, the neutral is connected
to the insulated buss bar and has all of the neutrals coming from the house
circuits connected to it. The buss bar that is bonded to the frame has all
of the ground wires from the circuits going to it, and is connected to the
ground wire in the service feed cable.
This additional ground wire the inspector wanted was to be a #6 bare copper
wire connected at the main panel (service entrance) onto the ground/neutral
buss and then run to the sub panel and connected to the ground buss. (which
is bonded to the frame)
I believe Clair read my description correctly, and that the two #6 bare
copper and the ground conductor in the cable are connected to the same
things in each panel, and they are parallel, and that the #6 is indeed above
code and unnecessary.
If it is necessary, I sure would like to know the reasoning behind what it
does, and why it is necessary.
OK, go at it!
--
Jim in NC
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> I didn't get that impression. It sounded like he got fired for
>> enforcing nonexisting rules elsewhere, but the OP didn't say he was
>> fired for *this* case. The OP implied that he now suspects the
>> inspector's requirements *because* he was fired.
>>
>> So IMHO the case is - the OP is now suspicious, and wants a second
>> opinion. Are bare grounds required? Are ground loops legal?
>
> Bare grounds are not required and ground loops are not allowed. But -
> man... you read a lot more into that than I did.
>
> --
>
> -Mike-
> [email protected]
No, not fired on account of this case. Probably the same stuff that got him
fired, though. I never protested, but I also got off with only promising to
put the #6 in, and never did install it. Now, I am bringing everything up
to code and want to know what the code says about his extra wire.
What is this ground loop thing? I think that an extra wire connected to the
same thing on both panels as the ground wire in the cable would put them in
parallel, just like adding extra size to the cable ground conductor, not a
loop.
--
Jim in NC
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Yep. That is how it is.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
> Doug Winterburn wrote:
>
>>>
>> Not sure the extra heavy duty ground hurts anything, but make sure the
>> ground and neutral are not tied together in the sub panel - in other
>> words, separate neutral and ground bus bars and no bonding strap from
>> the neutral bus bar to the sub panel case.
>
> Echo
>
> --
>
> -Mike-
> [email protected]
>
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"Puckdropper" <puckdropper(at)yahoo(dot)com> wrote in message
news:[email protected]...
> "Morgans" <[email protected]> wrote in
> news:[email protected]:
>
>> OK, here is the deal. I have the original breaker panel fed by a 150
>> amp line off of a new panel necessitated when an addition was added
>> years ago. The sub panel is fed by a line with three conductors and
>> ground of the correct size.
>>
>> The inspector at the time ended up getting fired for enforcing code
>> that was not there. With this in mind, he said he wanted a #6 bare
>> ground wire to tie between the original panel and the new panel. That
>> means it would be in parallel to the ground in the service feed cable.
>
> I think we're getting confused here. How many pieces of copper are in
> the feed? 3 or 4?
4, but they are aluminum. Two hots and a neutral, all three insulated, with
additional bare conductor.
>
> A second wire, outside the feed, is connected from panel to panel as a
> ground, right?
>
>> Was he full of it when he told me this? I have been "neating up" the
>> panel along with my renovations for my new basement workshop. The old
>> panel was wired by a left handed chip, or a big bird, it was so messy.
>> I took all but about 5 circuits out and re-organized the whole thing
>> neatly and added a few new circuits for the shop. I feel much better
>> about it, and solved a few mysteries that had always bothered me.
>>
>> Jim in NC
>>
>>
>
> Puckdropper
> --
> Make it to fit, don't make it fit.
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"Mike Marlow" <[email protected]> wrote
> ??? Usually one would pull a 4 wire feed between the two - two hots, a
> neutral, and a ground - all of which are semi-wrapped around each other as
> a single bundle. So - nothing "outside the feed".
Which is exactly my beef. This guy wants an additional #6 outside the
feed.
--
Jim in NC
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<[email protected]> wrote
> Some of those panels CAN ge hacked or modified to separate the neutral
> from the ground - some can not easily be modified. (and if it is
> truely "modified" it is no longer an approved electrical device, so
> again it is not code compliant - so we will ASS U ME this is a
> compliant insulated(or isolated) neutral panel.
Correctly designed panel with a insulated lug for neutral with a connector
screwed onto the frame and into the holes in the lug and tightened down.
All I had to do is add a non insulated buss for the all of the grounds and
remove the bonding connector.
--
Jim in NC
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Morgans wrote:
> This additional ground wire the inspector wanted was to be a #6 bare
> copper wire connected at the main panel (service entrance) onto the
> ground/neutral buss and then run to the sub panel and connected to
> the ground buss. (which is bonded to the frame)
>
> I believe Clair read my description correctly, and that the two #6
> bare copper and the ground conductor in the cable are connected to
> the same things in each panel, and they are parallel, and that the #6
> is indeed above code and unnecessary.
That would be correct - in parallel if they are connected to the same things
on each end. Don't understand why your inspector required such a thing
though.
--
-Mike-
[email protected]
Doug Winterburn wrote:
> On 10/09/2014 04:14 AM, Mike Marlow wrote:
>> Morgans wrote:
>>
>>> This additional ground wire the inspector wanted was to be a #6 bare
>>> copper wire connected at the main panel (service entrance) onto the
>>> ground/neutral buss and then run to the sub panel and connected to
>>> the ground buss. (which is bonded to the frame)
>>>
>>> I believe Clair read my description correctly, and that the two #6
>>> bare copper and the ground conductor in the cable are connected to
>>> the same things in each panel, and they are parallel, and that the
>>> #6 is indeed above code and unnecessary.
>>
>> That would be correct - in parallel if they are connected to the
>> same things on each end. Don't understand why your inspector
>> required such a thing though.
>>
>>
> Probably thought that the grounding wire in the cable wasn't big
> enough?
Could be.
--
-Mike-
[email protected]
"Doug Winterburn" wrote in
Didja use the black gunk (anti-oxidant paste) on all the aluminum wire
panel connections?
You betcha. I payed attnson to all the sparkys I was around! I think mine
was green, though.
I was pretty sure this inspector was full of it. I never installed the
extra ground, and that was years ago. No problems. I ws just trying to do
everything exactly to code, and wanted to check for sure. I think it is
safe to say consensus was reached saying the second ground wire is not
necessary, and some have said it could be a violation or harmful.
I will go without it and sleep easy.
Jim in NC
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"John McCoy" wrote
The situation described has them both in the same conduit,
if I'm not mistaken. That's not a loop, that's just two
parallel conductors (and, if the conduit is EMT, then it's
three parallel conductors).
Residential, and not in conduit. This is SE (service entrance cable) and a
bare to be copper wire beside the se cable.
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[email protected] wrote:
>
> Insulated ground bus (one 's', two and it's a kiss)? Why insulated?
> It has to be bonded to the case. The neutral has to be isolated from
> the ground, sure.
No - an insulated neutral. The neutral must be isolated from the ground.
It's in the NEC.
.
>
>> The bonding strap located in the sub panel shall be connected to
>> the insulated ground buss.
>
> Again, why insulated? That makes *no* sense.
It's not required but it is common in a 4 wire feed.
--
-Mike-
[email protected]
[email protected] wrote:
> On Fri, 10 Oct 2014 18:35:35 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>> [email protected] wrote:
>>
>>>
>>> Insulated ground bus (one 's', two and it's a kiss)? Why insulated?
>>> It has to be bonded to the case. The neutral has to be isolated
>>> from the ground, sure.
>>
>> No - an insulated neutral. The neutral must be isolated from the
>> ground. It's in the NEC.
>
> Right, but that's *not* what Lew said. Go back and read what you
> snipped.
>
>
>>>
>>>> The bonding strap located in the sub panel shall be connected to
>>>> the insulated ground buss.
>>>
>>> Again, why insulated? That makes *no* sense.
>>
>> It's not required but it is common in a 4 wire feed.
>
> The ground bus is *not* isolated in a common panel. The neutral bus
> *is* (with a link to bond it in the entrance).
I think he was referring to a rubber insulated ground wire.
x
--
-Mike-
[email protected]
[email protected] wrote:
>
> Maybe, but that's not needed, either, if it's in conduit.
Not in conduit - but that information may have been presented after you
posted this
>
> OTOH, he said,
>
> "A sub panel requires an insulated ground buss as well as
> an insulated neutral buss."
>
> The "bus" is the multiple-tap connection point, not the wire between
> the boxes.
>
> We could also all be talking past each other. I wanted to get
> everyone on the same page, though.
Yup - there was indeed some confusion during the conversation, but I think
that's been cleared up now.
--
-Mike-
[email protected]
"Mike M" wrote
I'm confused by all this, but assuming your feeding your sub panel
with three conductors and a ground sized for the OCD then the only
reason I can think of for the #6 is that its a separate building and
he wants a grounding system which varies from jurisdiction to
jurisdiction. #6 being the largest size required to a grounding rod.
MikeM
Remember one of the other comments.
This same inspector was later fired for making people do sh*t that was not
required by code. He seemed to invent things along the way.
I suspect if I had reported him with my case, that would have been a few
days earlier that he got fired.
There is no reason in the world to require an additional ground. I knew
that, (or was pretty darn sure) but wanted to confirm it, and I know there
were several electricians in the group.
At any rate, I never did the "upgrade" then, and I'm sure not going to do it
now!
Jim in NC
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On Thu, 9 Oct 2014 19:54:54 -0700, "Lew Hodgett"
<[email protected]> wrote:
>
>"Morgans" wrote:
>
>> OK, here is the deal. I have the original breaker panel fed by a
>> 150 amp line off of a new panel necessitated when an addition was
>> added years ago. The sub panel is fed by a line with three
>> conductors and ground of the correct size.
>----------------------------------------------
>Somebody had it right.
>
>Mike Marlow maybe.
>
>A sub panel requires an insulated ground buss as well as an
>insulated neutral buss.
Insulated ground bus (one 's', two and it's a kiss)? Why insulated?
It has to be bonded to the case. The neutral has to be isolated from
the ground, sure.
>In addition, a sub panel must be able to disconnect all power
>under it's control in a maximum of six (6) motions of the hand;
>otherwise known as the six (6) hand rule.
>
>If more than (6) motions are required to disconnect all branches,
>then a main c'bkr is required.
The main may be one of the other breaker positions. That is, the sub
panel may be back-fed through one of the other breakers, as long as it
is clearly marked as the main (disconnect).
>SFWIW, a branch c'bkr located in the main panel and feeding the
>sub panel is also required.
Certainly. The wire has to be protected.
>The bonding strap located in the sub panel shall be connected to
>the insulated ground buss.
Again, why insulated? That makes *no* sense.
>The sub panel shall be fed by four (4) conductors (L1, L2, N and G)
>from the main panel.
If both hots are used, sure. Ground and neutral have to be separated.
>The neutral buss and ground buss in the main panel do not have
>to be insulated but often are.
*ONLY* if the main is the entrance panel. If it's another sub, they
must be separated there, too. In the entrance panel, the grounds need
not be separated from the neutrals but it's good practice.
>The bonding strap located in the main panel shall be connected to
>the ground buss.
If the main is the entrance.
>The neutral buss and ground buss in the main panel are tied together
>as well as the earth ground conductor which connects to the earth
>ground rod driven into the earth at the service point.
>
>The above meets code or did when I was in the business.
>
>Nothing else is required.
Lots of other things are required but...
On Sat, 11 Oct 2014 16:24:33 -0400, [email protected] wrote:
>On Sat, 11 Oct 2014 09:31:01 -0700, "Lew Hodgett"
><[email protected]> wrote:
>
>>>> OTOH, he said,
>>>>
>>>> "A sub panel requires an insulated ground buss as well as
>>>> an insulated neutral buss."
>>>
>>
>>-------------------------------------------------------------
>>
>>"John McCoy" wrote:
>>
>>> I wonder if the source Lew was quoting meant an "isolated"
>>> ground bus (i.e. isolated from the neutral) rather than
>>> insulated.
>>>
>>> Because I'm with you, insulated ground bus doesn't seem to
>>> make sense, when you're going to strap it to the case anyway.
>>------------------------------------------------------------------
>>If you read and understand what was written, you will see that
>>my comments are correct as written.
>>
>>The NEC does NOT permit multiple paths to ground, but rather
>>only allows a single path between a fault and earth ground.
>>
>>INSULATED neutral buss and ground buss bars mounted and
>>wired ONLY as described will meet those NEC requirements
>>of having ONLY a single path from fault to ground.
>
>Wrong. Ground bars are *not* insulated/isolated from the case.
>Neutral bars are and strapped when necessary.
Nowhere did he say what you say he said. He said: Insulated neutral
busses ---- and ground busses mounted and wires only as described ---
will meet those NEC requirements.
He did not say: Insulated neutral bus and ground bus bars --- mounted
and wires ONLY as described --- will meat those NEC requirements.
So no, he was NOT wrong.
You just chose to read it wrong.
>
>>Yes it does make a difference how a system is wired and the
>>equipment used in order to meet the NEC requirements.
>
>Yes, but you're still wrong.
And so are you - - - - in the interpretation of what he wrote.
On Wed, 8 Oct 2014 22:02:26 +0000 (UTC), John McCoy
<[email protected]> wrote:
>DJ Delorie <[email protected]> wrote in news:[email protected]:
>
>> If both grounds are
>> connected on both ends, there's a loop. Is a loop in a ground allowed?
>
>The situation described is topologically a loop, but not
>electrically.
>
>> Are ground loops legal?
>
>"ground loop" means something else in the world of electricity.
>
>John
A ground loop hums at about 60 hz as I recall, not that I ever hooked
up one. Well maybe one at a mic input.
Mark
On Fri, 10 Oct 2014 19:49:06 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>> On Fri, 10 Oct 2014 18:35:35 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> [email protected] wrote:
>>>
>>>>
>>>> Insulated ground bus (one 's', two and it's a kiss)? Why insulated?
>>>> It has to be bonded to the case. The neutral has to be isolated
>>>> from the ground, sure.
>>>
>>> No - an insulated neutral. The neutral must be isolated from the
>>> ground. It's in the NEC.
>>
>> Right, but that's *not* what Lew said. Go back and read what you
>> snipped.
>>
>>
>>>>
>>>>> The bonding strap located in the sub panel shall be connected to
>>>>> the insulated ground buss.
>>>>
>>>> Again, why insulated? That makes *no* sense.
>>>
>>> It's not required but it is common in a 4 wire feed.
>>
>> The ground bus is *not* isolated in a common panel. The neutral bus
>> *is* (with a link to bond it in the entrance).
>
>I think he was referring to a rubber insulated ground wire.
Maybe, but that's not needed, either, if it's in conduit.
OTOH, he said,
"A sub panel requires an insulated ground buss as well as
an insulated neutral buss."
The "bus" is the multiple-tap connection point, not the wire between
the boxes.
We could also all be talking past each other. I wanted to get
everyone on the same page, though.
On Wed, 08 Oct 2014 17:24:31 -0400, [email protected] wrote:
>On Wed, 8 Oct 2014 15:54:43 -0400, "Mike Marlow"
><[email protected]> wrote:
>
>>[email protected] wrote:
>>
>>> The feed wire was a 3 wire+ground cable The ground was connected to
>>> both panels. Adding the #6 bare copper ground between the two panels
>>> would, by necessity and the nature of the circuit, mean that the bare
>>> ground WAS in parallel with the ground in the feed cable.
>>
>>No - it would not. To be in parallel both ends would have to share a common
>>connection. It is simply a branch back to the original ground - and that is
>>the purpose of it - so that there is only ONE path to ground. To be in
>>parallel, it would be necessary to put in an additional ground rod at the
>>sub panel end - which is not in compliance with NEC.
>>
No additional ground rod, and from the OP's initial post, it sure
SOUNDED like the external ground conductor went panel to panel. I MAY
have mis-interpreted the initial post. If both the cable ground and
the external ground went panel to panel, I am correct. If the external
ground ran from the service ground ROD to the second panel, you may
technically be right.
>>> If the ground in the feed cable meats the requirement of code (which
>>> I am 99.999% certain it does) then requiring the extra basre ground
>>> was a requirement beyond code, and he needed his knucles rapped good.
>>> I suspect this was not his first infraction for requiring "above code"
>>> - hense his firing. Good riddance.
>>
>>NEC requires a 4 wire feed to a sub panel - assuming 240v. Two hots, a
>>neutral and a separate ground that is only connected back to the main panel
>>ground (which makes it NOT in parallel). Does not matter what makes sense
>>to you - that is the NEC. As I said - the bare ground did not make any
>>sense to me and I'm not sure that's what was really specified but if it was,
>>don't make any sense - but the separate ground does indeed make a lot of
>>sense - it's the NEC.
> You definition is strange. 2 wires, connected to the same thing at
>each end, put the 2 wires in parallel, and they would share the fault
>load if power was to short to the panel frame at the "load " end.
>
>It is connected to the main panel ground at the main panel end. So is
>the bare (or green) wire in the 3 wire+ground cable to the sub panel.
>It is connected to the ground terminal of the sub panel. So is the
>bare wire (or green) in the cable from the main panel. That puts the
>two grounds in parallel. It is also "effectively" in parallel with the
>white neutral, although not "exactly".
On Wed, 8 Oct 2014 15:54:43 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>
>> The feed wire was a 3 wire+ground cable The ground was connected to
>> both panels. Adding the #6 bare copper ground between the two panels
>> would, by necessity and the nature of the circuit, mean that the bare
>> ground WAS in parallel with the ground in the feed cable.
>
>No - it would not. To be in parallel both ends would have to share a common
>connection. It is simply a branch back to the original ground - and that is
>the purpose of it - so that there is only ONE path to ground. To be in
>parallel, it would be necessary to put in an additional ground rod at the
>sub panel end - which is not in compliance with NEC.
>
>> If the ground in the feed cable meats the requirement of code (which
>> I am 99.999% certain it does) then requiring the extra basre ground
>> was a requirement beyond code, and he needed his knucles rapped good.
>> I suspect this was not his first infraction for requiring "above code"
>> - hense his firing. Good riddance.
>
>NEC requires a 4 wire feed to a sub panel - assuming 240v. Two hots, a
>neutral and a separate ground that is only connected back to the main panel
>ground (which makes it NOT in parallel). Does not matter what makes sense
>to you - that is the NEC. As I said - the bare ground did not make any
>sense to me and I'm not sure that's what was really specified but if it was,
>don't make any sense - but the separate ground does indeed make a lot of
>sense - it's the NEC.
You definition is strange. 2 wires, connected to the same thing at
each end, put the 2 wires in parallel, and they would share the fault
load if power was to short to the panel frame at the "load " end.
It is connected to the main panel ground at the main panel end. So is
the bare (or green) wire in the 3 wire+ground cable to the sub panel.
It is connected to the ground terminal of the sub panel. So is the
bare wire (or green) in the cable from the main panel. That puts the
two grounds in parallel. It is also "effectively" in parallel with the
white neutral, although not "exactly".
On Wed, 8 Oct 2014 22:02:26 +0000 (UTC), John McCoy
<[email protected]> wrote:
>DJ Delorie <[email protected]> wrote in news:[email protected]:
>
>> If both grounds are
>> connected on both ends, there's a loop. Is a loop in a ground allowed?
>
>The situation described is topologically a loop, but not
>electrically.
Actually, it is. If the two wires are routed separately (if they're
run absolutely together, its one wire), there is a loop or a "one-turn
transformer", if you will. That's why it's not allowed.
>
>> Are ground loops legal?
>
>"ground loop" means something else in the world of electricity.
No, it's the same thing for the same reasons (though perhaps different
outcomes).
On Wed, 8 Oct 2014 10:49:24 -0400, "Mike Marlow"
<[email protected]> wrote:
>Morgans wrote:
>
>> OK, here is the deal. I have the original breaker panel fed by a 150
>> amp line off of a new panel necessitated when an addition was added years
>> ago. The sub panel is fed by a line with three conductors and ground of
>> the
>> correct size.
>
>Just to clarify Jim - what was once the "original" panel is now a sub-panel?
>
>>
>> The inspector at the time ended up getting fired for enforcing code
>> that was not there. With this in mind, he said he wanted a #6 bare ground
>> wire to tie between the original panel and the new panel. That means it
>> would be in parallel to the ground in the service feed cable.
>
>No - it doesn't. The ground only shares one point in common between the two
>panels so it can't be in parallel. Not so sure about the #6 aspect of what
>he wanted, but the connection between the two panels (main and sub) is
>exactly to the NEC spec. If he got fired for that then whoever fired him
>should be fired themselves. It does not have to be a bare ground - an
>insulated ground is perfectly acceptable. Bare ground is only specified for
>grounding stakes.
The feed wire was a 3 wire+ground cable The ground was connected to
both panels. Adding the #6 bare copper ground between the two panels
would, by necessity and the nature of the circuit, mean that the bare
ground WAS in parallel with the ground in the feed cable.
If the ground in the feed cable meats the requirement of code (which
I am 99.999% certain it does) then requiring the extra basre ground
was a requirement beyond code, and he needed his knucles rapped good.
I suspect this was not his first infraction for requiring "above code"
- hense his firing. Good riddance.
"Mike Marlow" <[email protected]> writes:
> No - it doesn't. The ground only shares one point in common between
> the two panels so it can't be in parallel.
His point is that there are now TWO grounds between the panels, the
insulated one in the cable and a separate bare #6. If both grounds are
connected on both ends, there's a loop. Is a loop in a ground allowed?
> If he got fired for that
I didn't get that impression. It sounded like he got fired for
enforcing nonexisting rules elsewhere, but the OP didn't say he was
fired for *this* case. The OP implied that he now suspects the
inspector's requirements *because* he was fired.
So IMHO the case is - the OP is now suspicious, and wants a second
opinion. Are bare grounds required? Are ground loops legal?